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An anonymous reader writes with this excerpt from a Stanford news release:
"Stanford engineers have figured out how to simultaneously use the light and heat of the sun to generate electricity in a way that could make solar power production more than twice as efficient as existing methods and potentially cheap enough to compete with oil. Unlike photovoltaic technology currently used in solar panels — which becomes less efficient as the temperature rises — the new process excels at higher temperatures. ... 'This is really a conceptual breakthrough, a new energy conversion process, not just a new material or a slightly different tweak,' said Nick Melosh, an assistant professor of materials science and engineering, who led the research group. 'It is actually something fundamentally different about how you can harvest energy.' And the materials needed to build a device to make the process work are cheap and easily available, meaning the power that comes from it will be affordable."
The abstract for the researchers' paper is available at Nature.

Can anyone point me to a good cost/watt chart over time? I would love to be able to see how prices have dropped over the past two decades. I keep hearing that solar has to drop in price... but have no baseline to judge our progress.

What I want to know is what mechanisms are causing their Gallium-Nitride junction to conduct more reverse current above 227 C.

They are currently projecting operating at 200 C for max efficiency but if it's as I suspect -- increased current flow with higher temperature -- then they can modify the doping mixture to get even higher temps and therefore higher efficiencies.

This would also boost the Carnot Cycle efficiency limit for the secondary heat exchanger that operates after the GaN primary power generation.

What I want to know is what mechanisms are causing their Gallium-Nitride junction to conduct more reverse current above 227 C.
They are currently projecting operating at 200 C for max efficiency but if it's as I suspect -- increased current flow with higher temperature -- then they can modify the doping mixture to get even higher temps and therefore higher efficiencies.
This would also boost the Carnot Cycle efficiency limit for the secondary heat exchanger that operates after the GaN primary power generation.
I'm reading from the slides [nature.com].

You'll know after they receive the much deserved Patents, if this is proven correct.

The caveat on that chart is it tracks Silicon based technology only, so you only see the impact of thin films via market price pressures, not directly. FWIW.

No, it seems to track them regardless of manufacturing method, but the graph tracks some sort of average price index across all manufacturers. They mention in the news release that: "as of July 2010, there are now 518 solar module prices below $4.00 per watt (€3.20 per watt) or 36.4% of the total survey. [...] The lowest thin film module price is at $1.07 per watt (€0.86 per watt) from a United States-based retailer."

Another caveat: These are single-module, retail prices -- obviously it gets chea

The graph tracks Si module prices. It used to say that explicitly. That may or may not still be the case explicitly, but there just aren't that many thin film modules above 125W, which is what they do say now. IIRC they used to restrict it to mono-Si. Even if they are allowing multi-Si now, modules above 125 are less common in that product space because they have to be pretty big to pull in that much power, so mono-Si will be overweight in that chart, at the very least.

I was going to dismiss this as "not much movement" but then I remembered about inflation. $4.10 in 2010 would be about $3.30 in 2001, so 5.40/3.30 = about a 64% price improvement. That's fairly respectable, though it still looks like decades until it's 'cheap'.

Can anyone point me to a good cost/watt chart over time? I would love to be able to see how prices have dropped over the past two decades. I keep hearing that solar has to drop in price... but have no baseline to judge our progress.

It depends on what you want: space solar panels are the most expensive multi-junction technology, but achieve the highest efficiency.

If you're a huge company, you can get really great deals because you purchase whole manufacturing runs. This is also why it's hard for an individual to buy direct from any manufacturer: all their production capacity is probably already bought up by large companies, so you get the "seconds," the panels that those resellers decide they would like to sell to you (at a price mark up, of course).

Solarbuzz publishes an updated graph of $:W-peak [solarbuzz.com] in its monthly reports of solar PV module prices. The data comes from its own proprietary market research (which it sells in detail).

You can see that solar module prices are falling steadily, as they were until the Bush Bubble pushed them back up and held them steady until the Bush Crash let them drop again. We finally got back in 2010 to the lows we'd left in 2004, but the drop is leveling off again. Also note that those numbers are the average market price,

Solar array costs per watt have dropped considerably, but an array still costs an arm and a leg.

here are some reasons:
- Enough batteries to keep your freezer frozen through the night and maybe a couple cloudy days is expensive.
- Labor costs of installation are 25-50% of installation costs, but if you don't get it installed and inspected by the proper people, your home owners insurance will probably be canceled.
- It's very expensive to install enough panels to power multiple computers, multiple TV's, ACs, Fridges, Microwaves, and a multitude of other electronic devices. Customers need to reduce their power consumption before investing in a solar array.
- Tying your solar array into the grid is expensive. you can't just dump power into the grid. it has to be clean and in phase with grid power, and has to be installed by a certified electrician. (btw it's not just THE grid, it's the power companies grid. They tell you when you can use it. If the power goes down in your neighborhood they will turn off your inverter, because they need the lines powered down when the linemen are working on them.)

Labor costs are not going to go down drastically, so i don't know how much cheaper it can get to the end user. in addition, it seems that as panel costs go down, Inverters are getting more user-friendly, and hence more complex and expensive. inverters alone run from $5000 to $8000 these days.

I didn't really make it clear that it's an either/or situation. However, I was trying to explain that you don't really save anything by picking one over the other. I also wanted to show that labor costs are not going to go down, even if the equipment gets cheaper.

It can be really cheap if you just use batteries and DC appliances. you can install the system yourself if your competent. However, if your state offers rebates, you probably won't qualify for this type of system.

Stop the heat moving; insulate everything. Internal and external walls. Roofs, floors, refrigerators/freezers. If not vacuum panels, research into the production of really cheap aerogels for building, DIY materials and domestic devices would probably do more to

Most people don't suggest PURE solar, with enough batteries for the lows. And they -certainly- don't suggest BOTH buying batteries AND connecting to the grid, that'd be just plain dumb.

Solar and other variable and uncontrollable sources, work best when combined in a heterogenous mix. Some of the times that have no sun, do have wind and vice versa. hydropower is probably the best renewable source for those occasions when there's a peak in demand and not enough from the other sources.

Bring a product to market with all your so-called cheap abundant technology that never seems to pan out. I'm getting pretty damned tired of hearing about all these "advances" when nothing ever comes of it.

Most energy consumers can't afford the initial cost... And if they get a loan, interest costs eat up any savings that they might have gotten.

Actually, there is a solution to this problem... the Power Purchase Agreement [wikipedia.org]. It allows consumers to get a solar power system installed without having to put any money down, or pay any interest. You basically sign the agreement, let the company install the equipment, and then enjoy an instant, permanent decrease in your electric bill. My building is having a system

While that's one approach, it still doesn't address the fundamental problem: banks create the money supply by making loans. No loans, no money.

The investing class have the technical development of the world in a stranglehold: they feed money to developments that pay good dividends, and starve projects which would make their other investments obsolete.

sorta like credit unions, in that banks should be run for the benefit of their customers.

Or that the government should runt he banks?

Private banks make the money supply today. I believe that the government should make money, not JP Morgan Chase (in cahoots with the privately-owned central bank).

Not a whole lot would change in your day-to-day interaction with the banking system: you'd still have your choice of privately-run banks and credit unions. But this would be a seismic shift in the economic balance of power...

CSPV cells are one of the tech items that do in fact come to market. EMCOR and Spectrolab and others like Ammonix routinely bump their efficiency with new processes -- not just the efficiency of their "champion cells" but of their normal end product. In fact there have been upgrades done to concentrating PV plants whereby just by replacing the cells/heatsink, leaving all the dishes or whatnot untouched, they have increased output of the plant.

While most silicon solar cells have been rendered inert by the time the temperature reaches 100 degrees Celsius, the PETE device doesn't hit peak efficiency until it is well over 200 C.

Because PETE performs best at temperatures well in excess of what a rooftop solar panel would reach, the devices will work best in solar concentrators such as parabolic dishes, which can get as hot as 800 C.

Because PETE performs best at temperatures well in excess of what a rooftop solar panel would reach, the devices will work best in solar concentrators such as parabolic dishes, which can get as hot as 800 C. Dishes are used in large solar farms similar to those proposed for the Mojave Desert in Southern California and usually include a thermal conversion mechanism as part of their design, which offers another opportunity for PETE to help generate electricity as well as minimize costs by meshing with existing technology.

The fact that it is twice as efficient as a PV system is completely irrelevant, given that it will be competing with solar concentrators not PV systems.

The fact that it is twice as efficient as a PV system is completely irrelevant, given that it will be competing with solar concentrators not PV systems.

That depends on whether it can be deployed on a smaller scale or with different resource constraints than a regular solar concentrator. The standard solar-concentrator of an array of mirrors pointed at a central tower takes a certain amount of space, and there considerations about how the typically steam-powered generation process using that heat uses water

Melosh calculates the PETE process can get to 50 percent efficiency or more under solar concentration, but if combined with a thermal conversion cycle, could reach 55 or even 60 percent – almost triple the efficiency of existing systems.

I get the impression from the article that this tech would be impractical outside of situations where parabolic mirrors are not being used to focus the sun's energy onto such a solar cell. That makes it mostly impractical for everyday use.

Impractical for personal residence deployment and use, but I'd certainly call a big solar power generation station providing energy "everyday use". Or at least, I'd like for it to be an everyday use. Much like efficient windmills are much too large for my backyard, yet provide me with clean energy everyday.

It seems like every 6 months there's some big breakthrough in Solar that will make it many times better than existing technology. As far as I can tell none of it ever makes it out of the lab and into the market.

They all get bought out by the oil companies to keep it hidden and hush hush and then shelf the projects...same thing happened with those water powered motors that we are not supposed to know exists but have been shelved a long time ago...wiki i think has the links...

How can any water powered motor work without conflicting with the first law of thermodynamics?
From what I understand, both fuel and exhaust would be the same... water. Probably the same amount of it too. That sounds very much like free energy to me.

Don't get me wrong... I would really love for any type of water powered motor to work for real. (There appear to be several types.) But I've had a look around, and can't find any links describing the theory or science behind any type of water powered motor

actually when we are talking about water powered engines, we are really talking about steam powered engines...of which there are plenty of designs (older ones) as all the new and probably efficient ones have been bought up by the big oil/car companies.

Actually lots of it has. PV arrays are far more efficient now than even ten years ago, and the technologies around heat-based concentrators is also far advanced. There are parts of the country where its affordable to run a house entirely off solar -- something not possible a decade ago.

Just because the whole world hasn't converted doesn't mean the innovations aren't making it to the market, it just means even doubling efficiency hasn't helped make it cheaper than oil.

There is a big gap between lab results and making a product out of it.

1. There is the price to produce.2. Are the materials robust enough for real life.3. Is the research funded by an organization who will actually give it to industry. Oddly enough there are some groups who are so Anti-Business after there research is done they don't want to sell it to a big company as they would be selling out.4. Can the technology be reproducible.5. Is it safe.

I agree. I was going to reply and say the exact same thing. I'm sick of hearing about solar breakthroughs because nothing has been done to make this technology both affordable and practical for a homeowner. I live in one of the better parts of the country for solar power, and an installation would cost more than $15,000 to even begin to be practical.

I'd love to find a conspiracy theory in this, such as oil companies purchasing the patents and never developing the technology. Sadly though, I suspect much

These "overzealous" researchers are, in your overarching lump sum, the same people who create new technologies that do make it to market. You know for every new technology that makes it, there are several that don't. Is your solution to stop all the research so all the failures will stop breaking your heart?

I live in one of the better parts of the country for solar power, and an installation would cost more than $15,000 to even begin to be practical.

What part of the country is this where putting 15 grand in to your house is such an outrageous sum? A new roof, HVAC, siding, remodeling a room.. pretty much anything you do to your house is going to have a similar cost. And I guarantee none of them would give you the same return until you sell the house.

The key problem is that at $15,000, if your monthly electrical bill is $150, you need 100 months to pay for itself, which is about 8 years. If an investment doesn't pay for itself in 3 to 5 years, it's a poor monetary investment. At that point, simple economics is not a selling point, and you will have to sell the product on another real or perceived benefit, such as reduced grid dependence.

As dumb as this might sound my old neighbor had a coworker who created an engine that ran off water. The guy sold the patent to some company that was into oil for a few mil and it disappeared. It could be a bullshit story but my neighbor wasn't one to make things up and said it so matter of factly. Then of course are the youtube videos of things like this [youtube.com] (and to add to the conspiracy theory aspect of it if you search google it seems he died in a 'chemical accident')

You should start a community group and buy in bulk. In Portland, OR, a large number of people in one area of town did this, promising to only buy from 1 contractor (bunch of bid wars over that). That bulk buying power brought the cost down quite a bit. After federal and state tax credits were applied, I think the average price was like 3,500 or 4,000 dollars on what would have been a 12,000 dollar cost.

It looks like they could use this to retrofit current or proposed solar thermal installations. They're talking solar concentrators and temperatures well over 200C + combined cycle, so it would probably be a pretty minor change on the whole.

In average from the Nature paper to you being able to buy it in the store it should be usually 5-15 years, if its applied research. 5y is unlikely (developing and testing an industrialized process for thin film technology wiht composite technologies takes easily 2-3 years) and if its going to be more than 15y it may mean that it is to difficult, to expensive or has some other disadvantage - or something else is better.

While most silicon solar cells have been rendered inert by the time the temperature reaches 100 degrees Celsius, the PETE device doesn't hit peak efficiency until it is well over 200 C.

Because PETE performs best at temperatures well in excess of what a rooftop solar panel would reach, the devices will work best in solar concentrators such as parabolic dishes, which can get as hot as 800 C.

So still not practical for home roof top deployment. Most people will not want 800C )or anything close) on their roof tops even if it was light and portable.

If they could find a way to push this technology into the 100-150 degree range (thereby eliminating the need for concentration) and STILL maintain the 50% energy extraction the potential benefits are huge.

You've obviously never actually installed a roof, have you? It's not uncommon for the temperatures on the roof to be 50+ degrees higher than on the ground. New roofers die frequently because they don't realize that it's possible to sweat out water faster than their stomach can absorb. If the temperature in Phoenix is already 100 degrees on the ground it's not going to need a big temperature boost to bring it up to their desired temperature.

o still not practical for home roof top deployment. Most people will not want 800C )or anything close) on their roof tops even if it was light and portable.

Are you kidding? Add a couple of rotating mirrors and market it as a death ray. Rabbits getting into your garden? Neighbor's dog crapping on your lawn? Reflect that beam spot around and *poof*, no more problem!

They also don't have to be big. Fresnel reflector for example. Bog standard flat mirrors, arranged such that they reflect onto a focal point. Make the mirrors out of perspex and it's cheap and light as well as easily fitting onto a roof. You get a large mirror with a low profile, and can almost put the focus where you like.

Compete with oil? I'm going to guess that they mean with coal, as oil is rarely used as a fuel for power generating stations. Coal and natural gas, yeah, oil - not so much. In the U.S., anyway, only around 1% is generated by petroleum, whereas coal is about 45% and natural gas is about 23%.

Unless by "solar powered cars" they mean "electric cars attached to a solar-powered grid" that's pretty much exactly as stupid as the idea of a grid technology competing with oil. Cars don't have anywhere near enough surface area to produce useful energy, even if we didn't park them in garages all the time.

And in eastern Canada, hydro-electricity is generating above 80% of our needs, even generating electricity for the north-eastern USA states in some cases.

Here in Seattle, we're at almost 89% via hydro, nuclear at over 5.6%, and wind at over 3.4%. We're like at 2% or so (at least as of 2008) for coal & natural gas combined; that's well beyond what even I had thought for our area.

Compete with oil? I'm going to guess that they mean with coal, as oil is rarely used as a fuel for power generating stations

There's an awful lot of power generated all over the place (in stationary installations, mind you) with oil and with diesel. Furthermore, most of these are very dirty because they are small and it is actually more difficult to control the emissions in such a system. Of course, mostly we don't control emissions anyway, unless they have obvious effects.

You may be right technically, but in the long run, oil competes with all other energy sources. The reason we drive around in gasoline-consuming cars is because it's more efficient to carry around gasoline as an energy source than juiced-up batteries or hydrogen derived from electricity from the grid. If electricity became very cheap to generate thanks to solar power, and oil became more expensive due to scarcity, it would make more sense to use fuel cells or batteries as the power storage medium, obviating

Thermoelectric looks obvious, doesn't it? A few years ago I thought how convenient it would be to use the waste heat from my Diesel boat heater to generate electric power, and I contacted a manufacturer. The reply I got was "we're not even going to quote you because it's insanely expensive". Apparently thermoelectric generators are so expensive they only make sense on things like trans-Siberian or Alaskan gas pipeline monitors, where there isn't enough light for a solar PV supply and the cost of miles of environmentally resistant wiring would be even more prohibitive. Although Peltier generators are cheap, they are hugely inefficient - and even more inefficient in reverse. It would have been cheaper to cover the entire deck in solar panels.

You're absolutely right, current thermoelectric power sucks. Photon enhanced thermionic emission is much, much, much more efficient than seebeck effect conversion (which is what you mean when you say peltier).

Johnson Thermo-Electrochemical Converter System isn't a peltier type device. An excerpt from the link:
"The JTEC is an all solid-state engine that operates on the Ericsson cycle. Equivalent to Carnot, the Ericsson cycle offers the maximum theoretical efficiency available from an engine operating between two temperatures"
Carnot like efficiency is pretty amazing for a solid state device. Hell for any device...
Of course, even though it may be more efficient, it doesn't automatically make it more economica

I'm not sure what type of system you were attempting to buy, but a stirling engine (http://en.wikipedia.org/wiki/Stirling_engine) spinning a small generator wouldn't be very expensive. There are tons of DIY plans if you want a project. You can hand build a generator (bunch of magnets and copper wire) very easily. Or, like I just did, you can buy a old washing machine motor:), http://www.watchtv.net/~rburmeister/smart.html.

They aren't the only ones working on this process, I know a few others. Also, thermal and PV processes have been combined successfully before, unlike the claim in TFA - my own work centers on CPVT (Concentrating PV/Thermal) collectors. You can reach 40-50% efficiency like that. (Hell, you can get close to 30% just with triple-junction PV).

You know what? You like it. Otherwise you wouldn't keep reading the articles, or coming back to bitch about having to read them. If you don't like the articles, there are a million other web sites you could be reading instead.

No I DON'T like what Slashdot has become. It's like the National Enquirer of science news now. Maybe I'm wrong about *this* solar power discovery, but I'm tired of reading about phenomenal breakthroughs every couple of weeks; all sound and fury.

So if you could reflect the heat to generate power and use photovoltaics to generate power, could you also create them translucent to some spectrum of light? Then you could grow crops under the solar array, use the array for water capture so the irrigation would hold water better and provide power and temperature maintenance. This idea only works if photovoltaics and plants uses different spectrum to generate power/photosynthesize.

Its a new month. Along with the new month comes the "Latest and Greatest" in solar power innovation, this one far far more revolutionary than last months... We had electron dots, last month, we had microscopic cones capturing UV as well as thermal a few months before..... I go to the store and am looking at 25 year old technology. I know 'to market' is the hard part, but at what point will all of this innovation, magic and wonder actually be ready to buy? Is it like Tokamak reactors, 30 years for sure,

This seems to be the new scam for this decade. Your company/university/research-lab accounces a "breakthrough" using commonly available, cheap materials that "somehow" provide energy because the arrangement of these materials is the part no one has thought of before.

We've got: EEstor with their "ultracapacitor", Bloom Energy with the "Bloombox", Stanford's now got their Solar Gen whatever it is, there's the Science Fair Kid that made a 30% increase in PV efficiency, yadda yadda... Hell, a few weeks back even the Chinese announced a "new solar product" that was supposed to be more efficient...

Someone should go through the last 5 years of Slashdot and pull up all the articles about new energy technology and where they announce it will be available in stores in 5 years time, and let's see what the claims are versus what reality has brought us.

Because so far, all I ever see in stores or online is the same old crap that's been available since forever, plain old 12% efficient silicon-based PV panels, where you still need $2000 worth of them to run a fridge.

Recent grid solar installations are far more efficient and cost-effective than their counterparts from five years ago. I'd say that suggests all this research is going somewhere. What, you thought that each of these announcements about laboratory successes would instantly result in a new product on the shelf of your local Wal-Mart?

"Solar water heating [wikipedia.org] or solar hot water is water heated by the use of solar energy. Solar water heating systems are generally composed of solar thermal collectors, a water storage tank or another point of usage, interconnecting pipes and a fluid system to move the heat from the collector to the tank. This thermodynamic approach is distinct from semiconductor photovoltaic (PV) cells that generate electricity from light; solar water heating deals with the direct heating of liquids by the sun where no electri

In the article linked your spokesperson discussed the primary uses of a product like this being in solar thermoelectric farms. Did you guys ever consider what applications this technology might have on spacecraft? One of the biggest pain in the asses to deal with when designing a satellite is dumping all of the excess thermal energy off the dark side of the solar arrays (without it radiating into the rest of your spacecraft). If these solar cells actually get more efficient as they heat up, then less therma

Ditto. I'm getting truly sick of these "improvements in solar technology" stories that turn out to be little more than research lab oddities, penny stock scams, or something so expensive that it will never be commercially viable.

When it looks like Joe-Bob can buy a system for under a thousand at Wal-Mart, and the system is so idiot proof, that even Joe-Bob can plug it in and make it work without killing himself or burning down the trailer, you have something.

Until then, even if it works, solar is still just a rich man's toy.

Solar energy. It's NOT just a technical problem. It's an economic problem.

Even if the tech gets to a point where Joe-Bob can buy a 5,000 watt solar array at Wal-Mart for $999, he won't be able to install it permanently in a safe manner, because you're still dealing with 5,000 watts. It becomes nothing more than a fuel-less generator. Mounting it permanently on his roof, tying it in to his household wiring and setting up a grid-tie net-metering arrangement will still take the work of professionals.

Of course, we may someday get to a point where the process is simplified and routine enough that installation costs might approach something like putting in a tankless water heater, gas lines or satellite dish.

Wiring in a solar array to your household wiring is the work of professionals the same way wiring in a kettle is. Once it's common we will solve it the same way, you create a standard plug in a suitable location and just plug it in. The same thing is happening with roof lighting circuits. You used to have to get an electrician to wire each light in, now he puts a standard appliance socket near the hole in the roof and the light plugs in like any other appliance, now anyone can fit or change it.